1. Field of the Invention
The present invention relates to an apparatus for and a method of recording a two-dimensional image on a photosensitive medium by scanning the photosensitive medium with a light beam in main and auxiliary scanning directions.
2. Description of the Related Art
There has been developed a light switch for use as an optical modulator in recording two-dimensional images. The light switch comprises a two-dimensional array of small many movable mirrors that are individually displaceable depending on image information to be recorded. When a light beam is applied to the movable mirrors that have been displaced depending on the image information, the movable mirrors reflect respective light beams that are selectively supplied to an image recording medium to record a two-dimensional image based on the image information on the image recording medium.
A high-power light source is required to record two-dimensional images of sufficient density with light beams that are reflected by the small movable mirrors of the light switch.
One conventional arrangement that has been proposed to meet such a requirement is disclosed in Japanese patent publication No. 6-100829. In the disclosed system, as shown in FIGS. 12 through 14 of the accompanying drawings, a light beam L reflected by an optical modulator 4 is applied via a condensing lens 6 to a photosensitive medium 2 that is being fed in an auxiliary scanning direction indicated by the arrow Y, for thereby recording an image on the photosensitive medium 2. The optical modulator 4 comprises three arrays, juxtaposed in the auxiliary scanning direction, of movable mirrors 8 that are arrayed in a main scanning direction perpendicular to the sheet of FIG. 12 and the auxiliary scanning direction.
The light beam L is initially reflected by the first array of movable mirrors 8 which is located downstream in the auxiliary scanning direction, and applied via the condensing lens 6 to the photosensitive medium 2, forming pixels thereon, as shown in FIG. 12. As the photosensitive medium 2 moves in the auxiliary scanning direction, only the second array of movable mirrors 8 is actuated to guide the light beam L to the same pixels on the photosensitive medium 2 as those shown in FIG. 12, as shown in FIG. 13. Then, upon continued movement of the photosensitive medium 2 in the auxiliary scanning direction, only the third array of movable mirrors 8 is actuated to guide the light beam L to the same pixels on the photosensitive medium 2 as those shown in FIG. 12, as shown in FIG. 14. In this manner, three movable mirrors 8 are used per pixel on the photosensitive medium 2 to record an image with a sufficient amount of light.
For recording images on the photosensitive medium 2 in the manner described above, it is necessary to individually actuate the movable mirrors 8 of the optical modulator 4 in the main scanning direction, and also to control the arrays of movable mirrors 8 at a speed in synchronism with the speed at which the photosensitive medium 2 is fed in the auxiliary scanning direction. Such a process of actuating the mirrors 8 and controlling the arrays of movable mirrors 8 is complex.
It is a general object of the present invention to provide an apparatus for and a method of recording an image on a photosensitive medium with a light beam having an amount of light that is large enough to record images.
A primary object of the present invention is to provide an apparatus for and a method of recording a quality image on a photosensitive medium according to a simple control process.
Another primary object of the present invention is to provide an apparatus for and a method of recording a quality image on a photosensitive medium at a reduced cost.
Still another primary object of the present invention is to provide an apparatus for and a method of recording a quality image on a photosensitive medium at a high speed.
Yet another primary object of the present invention is to provide an apparatus for and a method of recording a quality image free of shading on a photosensitive medium.
According to the present invention, an optical modulator has a matrix of cells arrayed in main and auxiliary scanning directions, and controls a light beam emitted from a light source by controlling the cells arrayed in a main scanning direction according to image information depending on positions thereof in the main scanning direction and controlling the cells arrayed in an auxiliary scanning direction according to identical image information. A light collecting means collects light beams-controlled by the optical modulator in the auxiliary scanning direction and guides the collected light beams to a photosensitive medium.
Since a plurality of light beams are collected on each of pixels that make up an image and applied to the photosensitive medium, the image can be recorded on the photosensitive medium with a sufficient level of light energy. The cells of the optical modulator that are arrayed in the auxiliary scanning direction may be controlled based on identical image information. Thus, the image can be recorded on the photosensitive medium according to a highly simple control process.
Each of the cells comprises a movable mirror for reflecting the light beam, the movable mirror being displaceable depending on the image information to guide the light beam to the photosensitive medium.
By controlling the number of the cells arrayed in the auxiliary scanning direction for simultaneous activation, the amount of light of the light beams collected in the auxiliary scanning direction and guided to the photosensitive medium can be adjusted for each pixel in the main scanning direction.
The light collecting means may comprise a plurality of light collecting means arrayed in the auxiliary scanning direction for simultaneously producing images made up of a plurality of main scanning lines. Since the size of the light collecting means in the auxiliary scanning direction can be reduced, each of the light collecting means can be manufactured with ease.
If the photosensitive medium is made of a photosensitive material of high intensity reciprocity law failure, then the photosensitive medium can be fed at an increased speed in the auxiliary scanning direction to allow an image to be recorded thereon at an increased speed.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.